Furnace of the recuperative type



FURNACE 0F THE RECUPERATIVB TYPE Filed Oct. 14. 1925 nace Vof the metal recuperative type, ccn-4 hot and from H.

Patented Feb'. `7, 1928. I.

j UNITED STATES PATENT omer..

JALIES 10m HOTT, 0l' CANTON, 0R10.'

FUBNAGE 0F TE A'RIVE-TYPE.

appiieanon nieu 0mm i4, im. iro. casio. i

and air passed through or around them so.`

. as to be heated. The pipes have always burned out and the recuperator consequently destroyed.

Fig. 1 isa sectional view through a furstructed in-accordance' with my invention; Fig. 2 is a horlzontal sectional view through the portions lifted in elevation; and Fig. 3= $0 is a detailed sectional viewthrough one of the combustionor heat pipes. The accompanying drawing shows an ap-- plication ofthi's invention to Va.. continuous metal heating'furnace. The billets, for example, to be heated are successively intro- .duced broadside into the furnace as shown at 1, Fig. 1. They are then 'pushed by any suitable mechanism, Awhich is well known, throu `h the furnace towards the discharge so end o the furnace; here they are discharged by gravity down incline through door 2 and onto the table 3. Gas is su plied to the burner or port 7 by means o a'. header 4 and pipe Gleading therefrom into said port. Air is 'admitted'into the port- 7' from a header 5. Gas and air introduced through y port 7 burns at the discharge end of the furnace and the products ofcombustion pass inf the direction of the arrows toward the charging end of the furnacesA and gradually heat up the billets. The flue gases arethen directed downwardly thro through heating tubes or pipes 9 of the recuperator and .out the lue 10- to the stack 11. The air supp 'ed forcombustion is preheated l.by bemg'passed around'these -pipes through the Achainbei' 26. Construc tionsv somew at-similar to. this-have'been v used for many ears but they have not; begn4 successful for t efollo reasons.;v

First. At tim during e voperatioiiof a furnace it is necessary to shut practically all ofthe air oi of a This isne esiiry Ian n il The 'gaa'is very often 0n prevent mdp vtact with flue gas'.

`into the air lineand recu ratorand enough air ndsits way into-the course of the Hue gas to cause the gas to partially burn. The heat thus generated causes the recuperator tubes to become too hot and they are destroyed, since no air is circulating around' them.

, Second. Steel pipev has been used in vrecuperator constructions but the corrosion and heat Yfrom the exposed flame strikin the bare tubes have quickly "destroyed t ein. Thisdisadvantage has not been metlin cast liron recuperatr constructions.

Third. Explosions in recuperators are very; frequent due' to the combustion air supply' failing and the gas being forced into. the air pipe and air heating chambers before it is detected. The gas mixes with the air and very disastrous explosions have occurred.

. The above disadvantages have caused the metallic recuperators to be practically abandoned. Thi'sinvention is designed to overcome thesedisadvantages and will save the V*cast iron recuperators. vTo protect the recuperator from excessive heat as described above, I have provided .an air bleeder which is placed between the air recuperator and the air inletto the furnace. shown at 16, Fig. 1. This bleeder-is a b This bleeder is pass Whchwill allow -air to pass'thiough-t e recuperator but l not enter the furnace coinbustion chamber and so keep the metal re-4 cuperator at the desired temperature. The bleeder is in opera-tion any time the temperature of the recuperator reaches a point which endau'gers the structure of same. The air heating chambers 26 are providedlwith thermo-couples and instruments such as ,is depicted at 27, to indicate the temperaturel of the pipes. The bleeder valve maybe op erated h dowi'itake 8,

automaticall from one of these ther. ino-couples throng When I have used steel pipes-9 I have protected them from the'corrosion of furnace ases by lining them on the inside with a rel ctory sleeve 2 4. This shown in Figure 3. Thetile sleeve is slid into the pipes and grouted with irecla 25. Heat is readily conducted' through t linin but no corrosion of the tubes may take p ace due to con- In case the air supply veritable causes mec anically,A gas may' back am and there cause serious exp 'osionsf In order to prevent these explosions a jet of steam or connecting means 28. i

'fails due a unpref- 'V air is introduced through pipe 18 into the air pipe 15 so that this jet will act 1 n the capacity of an auxiliary device to mamtam the circulation of air through the recuperator chambers and prevent any gas -from finding its wa into the air chamber. This jet is automatlcally operated by means of a magnet 22 connected to the powercircuit of the fan motor 13 by the wires 23. When the power goesA oil, the magnet will release the arm 21 Fig. 1 and allow the lever 20 to fall and open the jet valve 19 in the pipe 18.-

In the operationof the improved furnacerecuperative chambers 26 heated bythe pipes 9 through which the products of combustion from the furnace pass on their way to the flue 10 and stackll.t .The air supplied for combustion is blown through the chambers 26 by the fan 12 Fig. 2 and is heated before being conducted' to the furnace through pipe .15 and pipe .5. If the recuperator becomes too hot the bleeder valve 17 Fig. 1 is-opened and an'additional amount of air is allo wed to be blown through the recuperator but does not reach the combustion chamber. If the power goes oil of vthe fan magnet 22 Fig.1

will release the arm 21, the lever 20 suspended from this arm willdrop and open the steam valve 19 and introduce a jet of steam into the ai;` pipe 15 to thereby maintain the llow or current of air through the recuperator chambers.

Various other applications may be made main idea of the method of asslng the required amount of air throng the recuperator and the protection of samefrom corrosion and overheating.

Having thus described the various features of my invention, what I desire to secure by Letters Patent, is:

1. Ina recuperative furnace, a combustion chamber, a recuperator chamber, heating tubes disposed in tbe recuperator chamber the combustion chamber and serving to conduct the roducts of combustlon away from the com ustio'n chamber,

anv air sup ly conduit for condu the heated air` om the refrigerator ehcallgerto 0 or supporting combustlon therein, pressure means for creating a. ilow of air 'from the recu ratorchamber through the air supply con uit to the'eombustion chamber, and temperature,controlled means for diminishing the air supply to the combustion chamber without varying the llow of air through the recuperator chamber whereby the fire tubesare cooled by a substantially uniform volume of air through the recuperator chamber.

2. In a recuperative furnace, a combustion chamber, a recuperator chamber, l heating tubes disposed in 'therecuperator chamber and serving to conduct the` roducts of combustion away from the com ustion chamber, an air supply conduit for conducting the heated air from therecuperator chamber to vthe combustion chamber for supporting combustion therein, pressure means or cre# ating a ilow of air from the recuperator chamber through theair supply conduit to the combustion chamber, and means operable according to the intensity of the heat in thil recuperator chamber for diminishing the air supply'to the combustion chamber without g the flow of air through recuperl vary ator chamber.

3. In a recuperative furnace, a combustion chamber, a recuperator chamber, heating tubes disposed in the recuperator chamber andserving toconduct the roducts of combustion away from the com ustion chamber, an air supply conduit for conducting the heated airV from the recuperatorL chamber to the combustion chamber for supporting combustion. therein, pressure means for creatmg a iiow of air from the recuperator chamber through the air supply conduit to the combustion chamber, a thermo-couple arranged in the recuperator chamber, and means o erable by the thermo-couple for varyingt e supply of air to the combustion 'chamber according to the intensity of the heat in the recuperator chamber and without varying the flow-of air through the said recuperator chamber. Y

4. In a recupcrative furnace, a combustion chamber, a recuperator chamber, heating tubes disposed in the recuperator chamber of this-invention without departing from the and serving to conduct the roducts of combustion away from the com ustion chamber,

an air supply conduit for conducting the heated air from the recuperator chamber to 'the Vcombustion chamber for supporting combustionY therein, pressure means. Yfor creatinga flow of air from the recu tor chamber through the air su ply con uit t0 the combustion chamber, a b ceder device inserted in said airvesupply conduit for bleed- 5. In a recuperaiive a f Y chamber-,fa recuperator chamber tubes in the recuperator chamber and serving-to conduct the roducts oafcom- .bustion any ffm *i* "9m chamber recuperator chamber.

for mamtaining a flow of 'air through the 6. In a recuperative furnace', a combustion chamber, a recuperator chamber, heating tubes disposed inthe recuperator chamber and serving to conduct the products oi combustion away from the combustion chamber, an air supply conduit for conducting the heated air from the recuperator chamber to the combustion chamber or supporting combustion therein, pressure means Vfor creating a ow of air supply from the recuperator 25 air through th'ef recuperator chamber vthrough the` air supply conduit to the combustion chamber, tive device adapted to n0 create a current of f1-,esame com? e air supply conduitY rmally inoperchamber, and

means operable upon pressure meansbecoming disabled for rendering said auxiliary means'operative.

I. In a reuperative furnace, a combustion chamber, a recupcrctor chamber, heatmg tubes in `the recuperator c and serving to vconduct the products of combustion away from the combustion chamber, airl air supply conduit for conducting the heated 'air from the recuperator chamber to the combustion chamber fer supportingcombustion therein, pressure means for creating a \tor chamber through the air supply conduit to theI combustion chamber,sa1 d pressure means embodying an electric motor, auxiliary means for creating a flow of air through the recuperator chamber, and means for rendering-said auxiliary means no erative and Yinclu device in circuit with said electric motor, for releasing said means when said motor is rendered inoperative.

, JAMES 'Ho'rr.

ilow of air supply from the recuperav an electro-magnetic 45 

